“LONDON — Britain’s coalition government survived the most serious challenge yet to its austerity plans on Thursday when Parliament narrowly approved a sharp increase in college fees. But violent student protests in central London, including an attack on a car carrying Prince Charles and his wife, Camilla, to the theater, provided a stark measure of growing public resistance.

The 62-year-old heir to the British throne and his 63-year-old wife, the Duchess of Cornwall, were said by palace officials to have been unharmed in the attack, which occurred when a group of about 50 protesters, some in full-face balaclavas and shouting “Tory scum!” and “It’s your government!” broke through a cordon of police officers on motorcycles while approaching London’s theater district in slow-speed traffic.

A photograph of the couple, in formal evening dress, showed them registering shock as protesters beat on the side of their armored, chauffeur-driven Rolls-Royce with sticks and bottles, smashing a side window, denting a rear panel and splashing the car with white paint. A Jaguar tailing the car and carrying a palace security detail was so battered that the police ended up using its doors as shields.

Prime Minister David Cameron called the attack on the royal couple’s car “shocking and regrettable.”

Other violence across the city center continued into the night, with demonstrators trying to smash their way into the Treasury building at the heart of the Whitehall government district with makeshift rams made from steel crowd barriers, shouting “We want our money back!” The protesters set small fires and clashed with riot police officers and mounted units that formed cordons outside government buildings. BBC reporters at the scene wore helmets as the rioters threw shattered blocks of steel-reinforced concrete.

Scotland Yard said at mid-evening that at least 12 police officers were injured, six of them seriously, including one who was taken unconscious to the hospital after falling or being pulled off his horse. At that point, one large fire was still burning in front of the Palace of Westminster, seat of the House of Commons. At the height of the unrest, rioters threw snooker balls, lighted flares and fireworks at the police, and tried to topple statues in Westminster Square, across from the Commons. At least 43 were arrested.”